Rocker upgrade for 95 3100

[95Achieva]

Have a 95 Achieva with a 3100 engine. Car runs pretty strong for a basically stock motor (around 16 flat in quarter), but I would like to turn it up a notch. The stock rockers are the stamped variety. From reading previous posts, I believe that the stamped 3100 rockers are 1.5 ratio, and the later roller rockers are 1.6 ratio. Have a few questions on swapping these rockers:

Will roller rockers from any 3100 or 3400 easily bolt on, or are certain years an easier swap?

Are all roller rockers on the 3100 or 3400 motors 1.6 ratio, or only on certain years?

Are any changes to the studs necessary for the swap?

Is there any difference between the pushrods currently in my engine and the ones for later 3100 or 3400 engines that came with roller rockers? If there are differences, which ones should be used for the swap?

Anyone know if the stock valvesprings can handle the extra lift, or should the springs for a later, roller rocker-equipped 3100 or 3400 be used?

Since the ratio change has only a negligible effect on duration, will the rocker swap cause any problems with the computer?

Thanks...any information or tips will be greatly appreciated.

[bszopi]

Well, first of all, you can't bolt roller rockers to 95 heads cause they don't have the notches required for the pedestals. SO... unless you want to swap heads, there really isn't a need to answer the rest of the questions yet.

[v6h.o.]

brad i have seen some 95's with the notches cut into the heads, and the stamped steel rockers with guide plates used.

im thinking there was a tooling change to alow for the start of the 96 roller rockers to begin when some of the 95's were being produced.

like i say ive only seen it on a few but there have been some 95's ive pulled valve covers off of at work, and they've got the provision for the 1.6:1 pedestal mounts.

otherwise your looking at either a setup from Comp cams or Crane cams if you dont have the pedestal mount notch, and if you dont swap heads.

[ikessky]

im thinking there was a tooling change to alow for the start of the 96 roller rockers to begin when some of the 95's were being produced.

like i say ive only seen it on a few but there have been some 95's ive pulled valve covers off of at work, and they've got the provision for the 1.6:1 pedestal mounts.

That is probably exactly what happened.

otherwise your looking at either a setup from Comp cams or Crane cams if you dont have the pedestal mount notch, and if you dont swap heads.

Couldn't you use the Comp's or the Crane's with the newer 3x00 heads also?

[v6h.o.]

Couldn't you use the Comp's or the Crane's with the newer 3x00 heads also?

yeah, i use the Comp Cams 1.6:1 roller tips on my engine, that with the GM adjustable rocker stud # 476530. you have to grind out the guide plates for this ratio. but the 1.52:1's fit with no problems as well.

[95Achieva]

Thanks for the info.

The part numbers I've seen online for the pushrods and camshaft appear to be the same for 3100's with stamped rocker arms and those with roller rockers. Can anyone confirm if the parts are interchangeable on these engines?

[ikessky]

yeah, i use the Comp Cams 1.6:1 roller tips on my engine, that with the GM adjustable rocker stud # 476530. you have to grind out the guide plates for this ratio. but the 1.52:1's fit with no problems as well.

Which ratio are you grinding for, the 1.52 or the 1.6?

[robby1870]

You have to grind for 1.6s, been there, done that